Generally, in order to have a relatively short development period when processing a light-sensitive material, the developing temperature is gradually increased to about 27.degree. C. or more. Shorter developing times can be obtained by using an automatic developing apparatus capable of carrying out rapid development processing with good reproduction as described in U.S. Pat. Nos. 3,025,779 and 3,672,288, and Rodal Technol., 44, No. 4, 257-261 (1973). The automatic developing apparatus generally includes a developing bath, a stopping bath, a fixing bath, a water wash bath and a drying zone. The conveying rate of films and processing temperature can be controlled within the apparatus.
Farnell et al. (J. Phot. Sci., Vol. 18, page 94 (1970)) discloses that the covering power of a photographic light-sensitive material using a silver halide emulsion can be improved by varying the degree of hardening of the gelatin binder in order to vary the degree of swelling in the developing solution. It has been noted that the covering power increases with a decrease in the degree of hardening of the silver halide light-sensitive layer by reducing the amount of a hardening agent used. However, if the degree of hardening is extremely low, the strength of the emulsion layer deteriorates remarkably. Accordingly, when processed with the above described automatic developing apparatus, the silver halide emulsion layer is easily separated from the support and/or the emulsion layer is easily scratched by handling during the processing. Further, as another problem, the binder which may come out of the light-sensitive material, alone or by bonding to other components in the processing solution and/or the light-sensitive material, sometimes forms insoluble sediments in the processing solution in the automatic developing apparatus. Such insoluble sediments in the processing solution are generally referred to as "scum" in this field. When scum is formed in the processing solution, it adheres to the light-sensitive material passing through the automatic developing apparatus resulting in a considerable amount of stain. The scum adhering to the light-sensitive material causes remarkable deterioration of the quantity of images on the light-sensitive material, by which the commercial value is lost entirely.
Further, if high temperature rapid treatment is carried out, the photographic light-sensitive emulsion layer and other layers swell and soften excessively. When this happens it causes the physical strength to deteriorate and frequently causes the formation of network patterns called reticulation on the surface.
Accordingly, the degree of hardening of the silver halide emulsion layer must be increased to some degree in order to aid in avoiding the above described problems. However, as the degree of hardening is increased the covering power decreases. Although there are many known methods of hardening the silver halide emulsion layer, none of them overcome the above described contrary relationship.
As a result of extensive investigations relating to improving such problems, it is found that the drawbacks caused by scum can be substantially eliminated where the hardness of the light-insensitive uppermost layer (hereinafter, referred to as "uppermost layer") is increased utilizing a hardening technique capable of controlling the hardness of the uppermost layer and that of the silver halide emulsion layer, separately (i.e., selective hardening of the layers).
When dealing with a multilayer coating material, if the uppermost layer is hardened so as to have a hardness higher than that of the lower layer, network patterns called "reticulation" occur, and resulting in deterioration of the covering power, when high temperature treatment is utilized (edited by R. J. Cox, Jojo et al., Photographic Gelatin, pages 49-61 (1972), Academic Press).
In order to prevent the occurrence of reticulation, carboxylated methyl casein or sodium ethyl cellulose sulfate may be added to the uppermost layer as described in U.S. Defensive Publication No. 887,012. Alternatively, it is possible to add a carboxyl group containing polymer as described in Japanese Patent Application (OPI) No. 36021/77 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") or an acid-treated gelatin as described in U.S. Pat. No. 4,266,010. However, these methods are not always suitable, because the polymer dissolves in the processing solution during processing which tends to form scums. Furthermore, these processes have many production problems.